Title: Life Around Stars: Habitable Zones Grade Level: 9th Grade Course: Earth Science
Lesson Overview:
In this lesson students are going to learn about what makes a planet habitable for life and how the area of habitability around a star can vary with the star’s luminosity. First students are going to read and analyze an article that discusses the general characteristics and basic information of our star, the sun. After, students will identify and discuss the features that make a planet habitable. Students will be placed into one of six groups to work in for the lab. Students will conduct an experiment where they are going to investigate the “Habitable Zone” for three stars with different luminosities. From this experiment they will be expected to determine how the luminosity of the star can affect the size of the habitable zone of the planets around it. Students will be making a cardboard platform with 1cm measurements and strips of temperature sensitive paper to determine where the inner and outer boundary of the Habitable Zone is for the star. Light bulbs will be used as the model for the stars. Students will be measuring their boundaries for three stars with varying luminosities (wattages). After students complete their lab they will be required to graph their data and answer a set of questions to help analyze their data and help them draw conclusions. Some of the questions will require students to apply not only the knowledge gained from this experiment but prior knowledge of stellar evolution and the solar system. These questions are designed to show students how everything they are learning is connected. To assess the students’ understanding of the lab, they will also be required to present their findings individually in a formal written lab report.
Learning Performances:
From this lesson students will be able to:
Identify the general characteristics of our sun
Identify key features that would allow a planet to support life
Define what a habitable zone is
Model the habitable zones around model stars of differing luminosities
Graph the location of a habitable zone
Interpret data and draw conclusions about the habitable zones around stars
Apply evidence from the lab to explain their own solar system
Describe how the size of a star’s Habitable Zone can vary with the change in a star’s luminosity
Apply prior knowledge of stellar evolution to describe how the age of a star can affect the size of its Habitable Zone
Present data and conclusions in a formal written lab report
A 12”x12” temperature sensitive liquid crystal sheet (to be cut into 24 strips)
3 lamps
2 pairs of bulbs with 3 different wattages (total of 6 bulbs)
Time required: (Three 50min periods)
Day 1- The Sun & Defining a Habitable Zone
10 min – Divide students in groups/ read Sun article
10min – Discussion of article sections in groups
15min – Class discussion of important information
10min - What makes a planet habitable?
5min – Defining a Habitable zone
Day -2 - Overview and Preparation
5min- Opening discussion
10min – Assigning of groups, overview of lab/explanation of preparation
30min – Groups prepare cardboard squares
5min – Clean up
Day- 3 – Lab Experiment
10min – Distribution of handouts, reviewing procedure of lab
30min – Lab experiment (10min per station)
10min – Groups review data, create graph, and draw conclusions
Instructional Sequence for Day 1
Introducing the lesson:
I will begin the class by dividing the class into four groups. I will hand out the article “Sun, the solar systems only star” and each group will be assigned a quarter of the article to read. Once each member of the group has read their assigned section, the group as a whole will come up with 5 facts that they felt were important in their article section that they should share with the class.
Instructional Activities:
Once each group is done finding 5 facts the class will come together and each group will present their facts in the order in which their sections came in the article. As each group shares their findings the class will discuss them. The discussion will allow students to become familiar with our solar system’s star and allow students to use their prior knowledge of what they have learned so far in the unit to understand what kind of star it is and what properties it has.
After the discussion I will ask the students: What makes a planet habitable? Why is Earth the only planet (that we know of) with life? What makes it different from the other planets? The responses given will be written on the board. If it hasn’t been included in the list I will ask the class if water is important. If it’s already included, I will ask the students what makes it important to life? After listening to the responses I will guide the discussion into how water affects its own environment because it needs a lot of energy to freeze or boil. The liquid cannot change its temperature until it has completely altered its state into a solid or a gas. Next, I will ask students what allows are planet to maintain a temperature to keep water a liquid. Students will be encouraged and guided into discussing the heat source from the sun and the distance that the earth is from the sun, which allows the water on our planet not to boil from being too close and hot or to freeze from being too far away.
Concluding the Lesson:
After I will tell the class that the distance from a star where a planet can maintain liquid water marks the boundaries of what is known as the “Habitable Zone.” A planet that is in the Habitable Zone of a star and can maintain liquid water and has the potential to support life. In our solar system Earth is the only planet within the Habitable Zone of the Sun.
Instructional Sequence for Day 2
Introducing to Lesson:
At the start of class I will ask the class what a Habitable Zone is to review where the class last off the previous day. After a brief discussion about it, I will pass out the lab overview, procedure, and platform setup sheet. I will explain to the class that they will be conducting an experiment where they are going to investigate the “Habitable Zone” for three stars (light bulbs) with different luminosities. From this experiment they will be expected to determine how the luminosity of the star can affect the size of the habitable zone of the planets around it. Students will be assigned to one of six groups that I make prior to the class. I chose to make the groups for this activity because this lab can be complicated with the setup and the group station rotations. I thought that the entire lab would run smoother if students were put into groups where their chances of fooling around and misbehaving decreased.
Instructional Activities:
The students will be guided step by step on how to make their cardboard platforms that will be placed around their stars to estimate the habitable zones. I will model each step for the groups as they follow along because the directions can be very confusing and they require the groups to make a lot of specific measurements. The groups are going to have to cut out a circle in the center of the cardboard (3cm radius) where the light bulbs will fit in. Around the center of the circle they will be using the compasses to draw 9 circles with 1cm of spacing in between them. Once the circles are drawn they will tape 8 strips of the temperature sensitive paper diagonally from the center hole.
Once each group is done making their platforms, I will model for them how they should place their platforms around the light bulbs when they are doing the experiment. I will also show them the light bulb stations and explain to them what station their group will start at the next day as well as how each group will move through the three stations so the lab can be started right away with little confusion. Each group will be going through three stations, each station with a different light bulb wattage. There will be a total of six stations, two stations per wattage. This allows for all the groups to start at a station and quickly rotate through three of them.
Concluding the Lesson
When the explanation of the lab is done, I will explain to students that they will be expected to write a formal lab report for the experiment. They will be allowed to review and discuss their data and make conclusions with their group but they must all individually write their own lab reports. Once all questions and concerns about the lab and the lab report are addressed, students will spend the last five minutes of class cleaning up the messes made from making their platforms.
Instructional Sequence for Day 3
Introducing the lesson
At the beginning of class I will pass out to students the worksheets where they will be writing their hypotheses, recording their data, drawing their conclusions, and answering questions that further analyze their findings. I will briefly remind students of the group rotations and what they should be doing at each station. Before starting, one member from each group will put their cardboard platforms on the light bulb of their starting station so the temperature strips can equilibrate to the thermal field around the light bulb. While the strips are equilibrating, each group will determine their criteria for defining the inner and outer boundary of the habitable zone by the color display of the strips. The strips of temperature sensitive paper will display a rainbow colored pattern in response to the amount of heat given off by the light bulb (purple being closest to the bulb and reddish orange being the furthest). Therefore, groups need to determine which part of the rainbow band will define the inner and outer boundary of their habitable zone. Each group doesn’t have to have the same criteria. After determining their criteria, students will make a hypothesis as to how the size of the habitable zones will change with the change of the stars luminosity (light bulb wattage).
Instructional Activities
Once students determine their criteria and hypothesis each group will have 10 minutes at each station to measure and record the distances between their light bulb and the inner and outer boundaries of each strip on the platform. Once students finish they will repeat the same procedure for the remaining two stations with different light bulb wattages. After each group has rotated through their three stations they will turn off the light bulb at their station and as a group average the distances of each boundary from each light bulb and make a graph. The graph will be of the inner boundary distance from the center of the bulb (in cm) plotted against the wattages of the light bulbs. The graph will also include the plot of the outer boundary distance versus the wattage of the light bulb. Once students plot their graphs they will answer the questions that follow on the sheet.
Concluding the Lesson
During the last five minutes of class students will clean up any mess that has been made and remove the platforms from the station they were last at after the bulb has cooled down. If students are unable to finish their graphs or the questions they will have to finish them at home for homework. The answers to the questions and the data collected by each group will be shared and discussed as a class the following day befoore starting the next topic.
Assessing Student Understanding
The students will be assessed by:
Participation in discussion
Their ability to work and cooperate well in a group
The completion of the their lab worksheets
The quality of answers given for the lab questions
How well their data and evidence support their conclusions drawn from the experiment.
The completion of a well written formal lab report
Cautions:
Since the students will be working with light bulbs that can get extremely hot I will need to make sure that they don’t burn themselves. To do this I will tell them to not touch the light bulbs when they are lit and that they shouldn’t place or remove the platforms onto or from the bulbs when they are lit. Students will only be allowed to move platforms when the light bulbs are off and are cooled. Another caution is to make sure that the holes the students are cutting in the center of their platforms are large enough to fit around the bulb without touching it. If students’ holes are too small and make contact with the light bulb, the cardboard can have the potential to catch on fire. Once the holes are cut I will go around to each group and make sure that they are large enough. Another option is for me to precut the holes into the cardboard so there won’t be any concern about their sizes and so none of the students can accidently cut themselves trying to make the holes. One last caution needed to be taken for this experiment is to make sure that the lamp sockets used are rated for the highest-wattage bulbs being used in the experiment. Again, this is to avoid any potential fire hazard.
Title: Life Around Stars: Habitable Zones
Grade Level: 9th Grade
Course: Earth Science
Lesson Overview:
In this lesson students are going to learn about what makes a planet habitable for life and how the area of habitability around a star can vary with the star’s luminosity. First students are going to read and analyze an article that discusses the general characteristics and basic information of our star, the sun. After, students will identify and discuss the features that make a planet habitable. Students will be placed into one of six groups to work in for the lab. Students will conduct an experiment where they are going to investigate the “Habitable Zone” for three stars with different luminosities. From this experiment they will be expected to determine how the luminosity of the star can affect the size of the habitable zone of the planets around it. Students will be making a cardboard platform with 1cm measurements and strips of temperature sensitive paper to determine where the inner and outer boundary of the Habitable Zone is for the star. Light bulbs will be used as the model for the stars. Students will be measuring their boundaries for three stars with varying luminosities (wattages). After students complete their lab they will be required to graph their data and answer a set of questions to help analyze their data and help them draw conclusions. Some of the questions will require students to apply not only the knowledge gained from this experiment but prior knowledge of stellar evolution and the solar system. These questions are designed to show students how everything they are learning is connected. To assess the students’ understanding of the lab, they will also be required to present their findings individually in a formal written lab report.
Learning Performances:
From this lesson students will be able to:
Links to Standards or Benchmarks:
Learning Goal 1
Materials Needed:
Time required: (Three 50min periods)
Day 1- The Sun & Defining a Habitable Zone
10 min – Divide students in groups/ read Sun article
10min – Discussion of article sections in groups
15min – Class discussion of important information
10min - What makes a planet habitable?
5min – Defining a Habitable zone
Day -2 - Overview and Preparation
5min- Opening discussion
10min – Assigning of groups, overview of lab/explanation of preparation
30min – Groups prepare cardboard squares
5min – Clean up
Day- 3 – Lab Experiment
10min – Distribution of handouts, reviewing procedure of lab
30min – Lab experiment (10min per station)
10min – Groups review data, create graph, and draw conclusions
Instructional Sequence for Day 1
Introducing the lesson:
I will begin the class by dividing the class into four groups. I will hand out the article “Sun, the solar systems only star” and each group will be assigned a quarter of the article to read. Once each member of the group has read their assigned section, the group as a whole will come up with 5 facts that they felt were important in their article section that they should share with the class.
Instructional Activities:
Once each group is done finding 5 facts the class will come together and each group will present their facts in the order in which their sections came in the article. As each group shares their findings the class will discuss them. The discussion will allow students to become familiar with our solar system’s star and allow students to use their prior knowledge of what they have learned so far in the unit to understand what kind of star it is and what properties it has.
After the discussion I will ask the students: What makes a planet habitable? Why is Earth the only planet (that we know of) with life? What makes it different from the other planets? The responses given will be written on the board. If it hasn’t been included in the list I will ask the class if water is important. If it’s already included, I will ask the students what makes it important to life? After listening to the responses I will guide the discussion into how water affects its own environment because it needs a lot of energy to freeze or boil. The liquid cannot change its temperature until it has completely altered its state into a solid or a gas. Next, I will ask students what allows are planet to maintain a temperature to keep water a liquid. Students will be encouraged and guided into discussing the heat source from the sun and the distance that the earth is from the sun, which allows the water on our planet not to boil from being too close and hot or to freeze from being too far away.
Concluding the Lesson:
After I will tell the class that the distance from a star where a planet can maintain liquid water marks the boundaries of what is known as the “Habitable Zone.” A planet that is in the Habitable Zone of a star and can maintain liquid water and has the potential to support life. In our solar system Earth is the only planet within the Habitable Zone of the Sun.
Instructional Sequence for Day 2
Introducing to Lesson:
At the start of class I will ask the class what a Habitable Zone is to review where the class last off the previous day. After a brief discussion about it, I will pass out the lab overview, procedure, and platform setup sheet. I will explain to the class that they will be conducting an experiment where they are going to investigate the “Habitable Zone” for three stars (light bulbs) with different luminosities. From this experiment they will be expected to determine how the luminosity of the star can affect the size of the habitable zone of the planets around it. Students will be assigned to one of six groups that I make prior to the class. I chose to make the groups for this activity because this lab can be complicated with the setup and the group station rotations. I thought that the entire lab would run smoother if students were put into groups where their chances of fooling around and misbehaving decreased.
Instructional Activities:
The students will be guided step by step on how to make their cardboard platforms that will be placed around their stars to estimate the habitable zones. I will model each step for the groups as they follow along because the directions can be very confusing and they require the groups to make a lot of specific measurements. The groups are going to have to cut out a circle in the center of the cardboard (3cm radius) where the light bulbs will fit in. Around the center of the circle they will be using the compasses to draw 9 circles with 1cm of spacing in between them. Once the circles are drawn they will tape 8 strips of the temperature sensitive paper diagonally from the center hole.
Once each group is done making their platforms, I will model for them how they should place their platforms around the light bulbs when they are doing the experiment. I will also show them the light bulb stations and explain to them what station their group will start at the next day as well as how each group will move through the three stations so the lab can be started right away with little confusion. Each group will be going through three stations, each station with a different light bulb wattage. There will be a total of six stations, two stations per wattage. This allows for all the groups to start at a station and quickly rotate through three of them.
Concluding the Lesson
When the explanation of the lab is done, I will explain to students that they will be expected to write a formal lab report for the experiment. They will be allowed to review and discuss their data and make conclusions with their group but they must all individually write their own lab reports. Once all questions and concerns about the lab and the lab report are addressed, students will spend the last five minutes of class cleaning up the messes made from making their platforms.
Instructional Sequence for Day 3
Introducing the lesson
At the beginning of class I will pass out to students the worksheets where they will be writing their hypotheses, recording their data, drawing their conclusions, and answering questions that further analyze their findings. I will briefly remind students of the group rotations and what they should be doing at each station. Before starting, one member from each group will put their cardboard platforms on the light bulb of their starting station so the temperature strips can equilibrate to the thermal field around the light bulb. While the strips are equilibrating, each group will determine their criteria for defining the inner and outer boundary of the habitable zone by the color display of the strips. The strips of temperature sensitive paper will display a rainbow colored pattern in response to the amount of heat given off by the light bulb (purple being closest to the bulb and reddish orange being the furthest). Therefore, groups need to determine which part of the rainbow band will define the inner and outer boundary of their habitable zone. Each group doesn’t have to have the same criteria. After determining their criteria, students will make a hypothesis as to how the size of the habitable zones will change with the change of the stars luminosity (light bulb wattage).
Instructional Activities
Once students determine their criteria and hypothesis each group will have 10 minutes at each station to measure and record the distances between their light bulb and the inner and outer boundaries of each strip on the platform. Once students finish they will repeat the same procedure for the remaining two stations with different light bulb wattages. After each group has rotated through their three stations they will turn off the light bulb at their station and as a group average the distances of each boundary from each light bulb and make a graph. The graph will be of the inner boundary distance from the center of the bulb (in cm) plotted against the wattages of the light bulbs. The graph will also include the plot of the outer boundary distance versus the wattage of the light bulb. Once students plot their graphs they will answer the questions that follow on the sheet.
Concluding the Lesson
During the last five minutes of class students will clean up any mess that has been made and remove the platforms from the station they were last at after the bulb has cooled down. If students are unable to finish their graphs or the questions they will have to finish them at home for homework. The answers to the questions and the data collected by each group will be shared and discussed as a class the following day befoore starting the next topic.
Assessing Student Understanding
The students will be assessed by:
Cautions:
Since the students will be working with light bulbs that can get extremely hot I will need to make sure that they don’t burn themselves. To do this I will tell them to not touch the light bulbs when they are lit and that they shouldn’t place or remove the platforms onto or from the bulbs when they are lit. Students will only be allowed to move platforms when the light bulbs are off and are cooled. Another caution is to make sure that the holes the students are cutting in the center of their platforms are large enough to fit around the bulb without touching it. If students’ holes are too small and make contact with the light bulb, the cardboard can have the potential to catch on fire. Once the holes are cut I will go around to each group and make sure that they are large enough. Another option is for me to precut the holes into the cardboard so there won’t be any concern about their sizes and so none of the students can accidently cut themselves trying to make the holes. One last caution needed to be taken for this experiment is to make sure that the lamp sockets used are rated for the highest-wattage bulbs being used in the experiment. Again, this is to avoid any potential fire hazard.
Sources:
Challenger Center for Space Science Education: http://www.challenger.org/lessons/32.pdf
Article:Sun, the solar system's only star
Teaching Resources:**
Next Lesson